KR101470974B1 - Maskless nanolithography system with silver planar lens - Google Patents

Abstract

The present invention relates to a maskless nanolithography system having a silver-plane lens, wherein a silver nano-layer formed of nano-silver on a planar lens is formed to have a certain thickness, and a beam transmitted through the surface plasmon phenomenon, By including a silver ring slit-shaped silver-flat lens that propagates up to 5 μm, it is possible to work in the intermediate field without using a mask, and at low cost, high throughput and high resolution.

Description

[0001] Maskless nanolithography system with silver planar lens [0002]

The present invention relates to a maskless nanolithography system, in which a nano-sized beam is propagated through a silver-plane lens to an intermediate-length region without using a mask, and an intermediate-length region And more particularly to a maskless nanolithography system having a silver-flattened lens capable of precisely controlling the working distance between the silver-plane lens and the wafer.

With the development of the semiconductor industry in recent years, the demand for nanolithography technology capable of realizing a very small pattern of less than 100 nm in lithography technology is greatly increased. Nano-lithography technology is also important for the development of next-generation semiconductor technology and nanotechnology.

In recent decades, nano-lithography techniques using optics have been developed. In the future, in order to commercialize nano-sized devices, it is indispensable to change the design of masks when using masks used in nanolithography, ≪ / RTI > For example, the cost of equipment for a single nano-nano-lithography process using optics exceeds $ 20 million. Because of this, the maskless nanolithography technique, which has been developed with various efforts to overcome the economic limitations of nano lithography using a mask, has a very good resolution of several to several tens of nanometers, There is an advantage that it can be produced.

However, the electron beam lithography (EBL) shown in FIG. 1A is extremely low in throughput due to a single electron gun, and equipment and an electron gun for forming a high vacuum state are relatively expensive, Due to the effect, it is necessary to perform lithography only on a conductive material and a special photo-resist which reacts with electrons such as polymethyl methacrylate (PMMA) is indispensable, and polymethylmethacrylate The selectivity of the etchant is low, and subsequent processes such as etching are difficult.

In addition, the focused ion-beam lithography (FIB) shown in FIG. 1B has extremely low throughput due to a single ion beam, and there is a problem that equipment and ion beam for forming a high vacuum state are relatively expensive.

Scanning Probe Lithography (SPL) shown in FIG. 1C has an extremely low throughput due to a single probe, and has a working distance of about 1 mm to the extent that the probe is in close contact with the sample in a near field. (Working Distance) is very short.

On the other hand, a multi-axial electron beam lithography technique has been developed as shown in Fig. 2 to solve the problem of low throughput by the single electron gun, the ion beam and the probe in Figs. 1A to 1C. However, in this multi-axis electron beam lithography, it is difficult to control the size and position of several beams at the same time, and problems such as electron charging effect as in electron beam lithography and electrostatic force of Coulomb remain.

As a result, the H. Smith research team of MIT in the United States has proposed Zone Plate Lithography (ZPL) that can be used as a maskless lithography device by using a number of rotation patterns as shown in FIG. However, this technology is ultimately a diffraction limited system, and since the wavelength of the light source must also be constantly reduced for nano-sized lithography, an expensive light source is essential for the same level of resolution as electron beam lithography . In addition, since the intensities along various optical axes are not uniform, diffraction limited system elements have a problem in that the dose of desired electrons is greatly changed even at a small optical axis displacement.

In addition, as shown in FIG. 4, the X. Zhang research team of UC Berkeley, USA, produced a device called Plasmonic Lens (PL) capable of producing strong focus in near-field, We demonstrated maskless lithography, called Flying Plasmonic Lens (FPL), which is mounted on a flying head and is sensitive to almost contact with a wafer rotating at high speed. A flying plasmonic lens having a resolution of approximately 80 nm can realize a high resolution exceeding the Diffraction Limit by using a strong electric field of a surface plasmon, When the distance from the near-field region is more than 100 nm, a strong focus can not be used. Therefore, there is a problem that the working interval between the device and the wafer must be maintained within a contact level, that is, within a near- This not only greatly limits the speed of maskless lithography, but also poses another problem that collision of the plasmon lens with the wafer occurs even in the presence of a small dust particle of 10 nm or more on the wafer.

(EBL, FIB, SPL), expensive equipment is required (EBL, FIB, SPL, ZPL), diffraction (ZPL), lithography (EBL, SPL, FPL) is possible only in the region of conductive material or near-field.

Therefore, there is a need to develop a maskless nanolithography technique capable of performing lithography even in an intermediate field (mid field) while being out of a near-field region while being inexpensive (low cost), high throughput and high resolution, In order to develop a nanolithography technique, there is a demand for a nano-optical device capable of propagating a nanometer-sized beam to an intermediate area while occupying a small space.

KR2007-92327 10 KR2004-105046 10

H. Smith, "A proposal for maskless zone-plate-array nanolithography," J. Vac. Sci. Technol.

In order to solve the above problems, the present invention is directed to a three-dimensional nano-position control device having a zone plate, which propagates a nano-sized beam to an intermediate length region by using an oval plane lens using surface plasmon, To provide a maskless nanolithography system having a silver-flat plane lens capable of performing precise position control in a medium-length area without using a mask, being inexpensive, capable of high-throughput and high resolution, There is a purpose.

According to an aspect of the present invention, there is provided a maskless nanolithography system having an astigmatism lens, comprising: a silver nano-layer formed of silver on a substrate and having a predetermined thickness; And a medium-length region of 1 to 5 [mu] m.

Here, the nano silver layer has a thickness of 80 to 120 nm.

Further, the silver plane lens is formed with a single ring slit-shaped metal opening, the radius R of which is 1,000 to 1050 nm, the width W is 320 to 370 nm, the period P is 5 to 10 μm , And the material of the metal is silver.

Here, the nanolithography system of the present invention further includes a zone plate formed on the silver nano-layer, wherein the zone plate detects the distance between the silver-plane lens and the wafer.

The distance between the silver-plane lens and the wafer is adjusted by the three-dimensional nano-position controller based on the distance detected from the zone plate.

In this case, the adjustment distance between the silver plane lens and the wafer is 1 to 5 um, which is an intermediate length region.

As described above, according to the present invention, it is possible to perform work in the intermediate length region without using a mask, and it is possible to achieve a low cost, high throughput and high resolution.

In addition, by providing a nano optical element capable of propagating a beam in a nanometer size to an intermediate length region while occupying a small space, time and cost required for a nanolithography process are remarkably reduced.

Further, the present invention relates to a device for producing nano-sized light, and is applicable to various industries such as semiconductor, display, imaging and solar light.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description, serve to further the understanding of the technical idea of the invention, It should not be interpreted.
1A is a perspective view schematically illustrating a conventional electron beam lithography.
1B is a perspective view schematically illustrating a conventional focused ion beam lithography.
Figure 1C is a perspective view schematically illustrating a conventional scanning probe lithography.
2 is a side cross-sectional view schematically illustrating a conventional multi-axis electron beam lithography.
3 is a diagram schematically illustrating a conventional zone plate lithography technique.
4 is a schematic view showing a maskless lithography technique of a conventional flying plasmonic lens technology.
5 is a conceptual diagram schematically illustrating a silver-plane lens in a maskless nanolithography system having a silver-plane lens according to the present invention.
6 is a graph showing the wave number of a surface plasmon used in the silver-plane lens of FIG.
FIG. 7 is a perspective view schematically showing a three-dimensional nano-position control device in a state in which the flat-plate lens and the zone plate of FIG. 5 are installed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the detailed description of known functions and configurations incorporated herein will be omitted when it may unnecessarily obscure the subject matter of the present invention.

<Configuration>

FIG. 5 is a conceptual diagram schematically showing a silver-plane lens in a maskless nanolithography system having a silver-plane lens according to the present invention, FIG. 6 is a graph showing the wave number of surface plasmon used in the silver- And FIG. 7 is a perspective view schematically showing a three-dimensional nano-position control device in a state where the flat-plate lens and the zone plate of FIG. 5 are installed.

The maskless nanolithography system having an astigmatism lens according to the present invention includes an eccentric plane lens 100 and a three-dimensional nano-position controller 200.

5, a silver nano layer 120 formed of nano silver is laminated on a substrate 110 made of glass or a crystalline material. The silver nano- . The silver-plane lens 100 is designed to form a beam of sufficiently small size so that it can be used for the purpose of nanolithography, and to form a beam of high quality, that is, a beam of high intensity intensity with minimal sidelobes. First, before explaining the structure of the silver plane lens 100, planar lenses and surface plasmas will be described.

Planar lenses are not traditional optical lenses, but they act like optical lenses that collect incident light in high efficiency. This plane lens does not cause image distortion phenomenon called monochromatic aberration, which occurs mainly in a general lens having a spherical surface. Spherical aberration, coma, and movie stigmatism are all eliminated and have well-defined diffraction limits. In addition, since planar lenses have a high degree of flatness, it is possible to eliminate the commonly occurring optical aberrations in conventional lenses with spherical surfaces, and to produce well defined foci. The surface of this planar lens forms antenna patterns of different shapes and sizes, which are directed in different directions and bring about a phase delay with radiation around the lens so that the more the rays fall from the center, the more refracted, And has an effect of focusing the incident light beam.

The plasmon phenomenon is a phenomenon that the free electrons of the metal are collectively resonated in the electromagnetic field applied from the outside, and the electromagnetic field around them is locally enhanced. This plasmon phenomenon (for example, electromagnetic waves) is generated on the surface of the metal and is developed to overcome the diffraction limit by collecting light in a volume smaller than the wavelength. In other words, using surface plasmon phenomena, it occurs at the metal surface and can gather light into a volume smaller than the wavelength, which allows the incident light to pass through a hole smaller than its wavelength. In order to make a small beam to overcome the diffraction limit, it is necessary to make the wavelength (? _{Sp, x} ) of the surface plasmon as small as possible. This is because the surface plasmon wave number of the metal- K _{sp, x} ) (for example, K _{sp, x} = 2π / λ _{sp, x} ). In order to propagate to an intermediate field (1 to 5 um) outside the near field, the imaginary part Im (K _{sp, x} ) of the surface plasmon wave number in the vertical direction z of the metal- Zero). Here, from the dispersion relation which considers the permittivity of the metal-dielectric material derived from the Maxwell's equation, λ _{sp, x} and K _{sp, x} can be summarized by the following [Equation 1] and [Equation 2].

[Formula 1]

[Formula 2]

It is necessary to appropriately adjust [Equation 1] and [Equation 2] in order to make a small beam using the surface plasmon and to propagate to the medium-length region, because it changes absolutely according to the permittivity combination of the metal-dielectric. (Re {K _{sp, x} }, Im {K _{sp, x} = 2π / λ _{sp, z} }) of the surface plasmons are assumed As shown in FIG.

Based on the above-described planar lens and surface plasmon, the silver-plane lens 100 according to the present invention has a nano-scale focal spot, a long working distance (WD) We investigated various nanostructures to satisfy the core requirements such as depth of field (DOF), high signal-to-noise ratio (SNR), and simple and simple manufacturing structure, Scalar Wave and Finite Difference Time Domain (FDTD) simulations. As a result, the structure satisfying all the above-mentioned core requirements can be obtained as a single ring slit-shaped metal opening (Metallic Aperture formed Single Ring Slit). In addition, it is possible to obtain a structure capable of obtaining a high-quality nano-sized beam up to 10 um in air through the interference of surface plasmon on the surface of a plane lens and transmission light, that is, a structure in which a radius R, a width W, ) And the kind of the metal and the thickness (t) of the metal can be obtained. At this time, the optimized radius R of the opening is 1,000 to 1050 nm, preferably 1,025 nm. In addition, the optimized width W of the opening is 320 to 370 nm, preferably 350 nm. In addition, the optimized period P of the openings is 5 to 10 um, preferably 8 um. In addition, the optimal metal is nano silver, and the optimal thickness t of the silver nanopowder 120 formed by the nano silver is 80 to 120 nm, preferably 100 nm. A basic structure of a single-ring slit-shaped silver flat-plane lens 100 as a nano-lithography focusing device using the interference between incident light and surface plasmon calculated through such optimization process is shown in FIG. The silver flat-plane lens 100 manufactured in this manner can propagate the incident wavelength of the incident light to the intermediate-length region through the near-field region, and can also transmit the far- Field), and in the present invention, it is adjusted to propagate only to the intermediate length region.

7, the three-dimensional nanoposition control apparatus 200 may be configured such that a nano-sized beam that has passed through the silver-plane lens 100 and propagated to the intermediate length region is focused on the wafer 230 with an accurate focus Plane lens 100 and the wafer 230 through a zone plate 210 so as to control the distance between the flat-plane lens 100 and the wafer 230.

The three-dimensional nano-position controller 200 recognizes the initial contact state between the silver-flat lens 100 and the wafer 230 on which the photoresist 220 is spin-coated, There is a need for an electrical or optical contact recognition technique capable of moving a few um after contact. A zone plate 210, which is a distance measuring device capable of recognizing the contact when manufacturing the silver-flat-surface lens 100, is constructed together with the silver-flat-surface lens 100 to meet this requirement.

Accordingly, when the distance between the silver-plane lens 100 and the wafer 230 is measured by the zone plate 210, the distance between the silver-flat lens 100 and the wafer 230 is adjusted.

7, the zone plate 210 is manufactured in the form of a multi ring slit on the plane of the nano silver layer 120, for example, at four corners of the silver plane lens 100 Is used to detect the distance between the silver plane lens 100 and the coated wafer 230 with the photoresist 220 to be exposed. For example, if the radius r _N of the _Nth concentric circle is designed to be f = 5 um in the expression (3), which represents the focal length f of the zone plate 210 with respect to the operating wavelength lambda, The focus of the zone plate 210 is focused on the wafer 230 when the distance between the wafer 100 coated with the photoresist 220 and the wafer 230 coated with the photoresist 220 is 5 μm, That is, a clear image change can be observed when the zone plate 210 is observed on the glass or quartz substrate side. As described above, the zone plate 210 can perform position detection to see how far the distance between the silver-plane lens 100 and the wafer 230 in the initial contact state is.

[Formula 3]

Here, the three-dimensional nano-position controller 200 measures the initial distance between the silver-on-planar lens 100 and the wafer 230, that is, the initial focal distance f by the zone plate 210, (f) moves the wafer 230 to an intermediate length of 1 to 5 nm. Of course, the distance between the silver-plane lens 100 and the wafer 230 is adjusted according to the position of the image formed by the beam passing through the silver-plane lens 100.

In addition, since the present invention relates to a device for producing strong nano-sized light, it can be utilized as a next generation display device such as a field emission display (FED) as well as a nano semiconductor field, and can be utilized as an imaging device. Diode can be improved. In addition, it is possible to improve the light receiving efficiency of the solar panel in the field of solar light, and it can be utilized in a large-capacity information storage device field such as a hard disk.

As described above, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

100: Silver plane lens
110: substrate
120: silver nano layer
200: 3D Nano Position Control Device
210: Zone plate
220: Photoresist
230: Wafer.

Claims (6)

A silver ring slit-shaped silver-flat lens 100 which is formed on the substrate 110 with a silver nano-layer 120 formed of silver to a thickness of 80 to 120 nm and which propagates a beam transmitted through surface plasmon development to an intermediate- Lt; / RTI &gt;
Wherein the intermediate length region is between 1 and 5 um. &Lt; RTI ID = 0.0 &gt; 21. &lt; / RTI &gt;
delete The method according to claim 1,
The radius R of the metal aperture is 1,000 to 1050 nm, the width W is 320 to 370 nm, the period P is 5 to 100 nm, 10 um,
Wherein the metal material is silver. The maskless nanolithography system of claim 1, wherein the metal material is silver.
The method according to claim 1,
Further comprising a zone plate (210) formed on the silver nanopowder (120)
Wherein the zone plate (210) detects the distance between the silver-plane lens (100) and the wafer (230).
5. The method of claim 4,
Wherein the distance between the silver-plane lens (100) and the wafer (230) is adjusted by the three-dimensional nano-position controller (200) based on the distance detected from the zone plate (210) Lean nanolithography system.
6. The method of claim 5,
Wherein the adjustment distance between the silver-flat plane lens (100) and the wafer (230) is in the mid-field range of 1 to 5 um.

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